West Germany sets sights on conventional weapons

West Germany will now try to beef up its conventional defense - and possibly deemphasize (though not renounce) nuclear defense.

This follows from the expressed views of the defense minister in the new conservative government, Manfred Worner.

Mr. Worner pins his hopes on fancy 1980s technology to offset the longstanding conventional imbalance between NATO and the Warsaw Pact. Basically, he is trying to counter the possible weakening of the protection of the ''extended deterrence'' from America's nuclear ''umbrella.''

In the early years of the alliance, NATO banked on defending West Germany's narrow east-west width (and the enclave of West Berlin inside East Germany) by NATO's superiority - or at least parity - in theater nuclear weapons. The reasoning was that no matter how much stronger Warsaw Pact conventional forces might be, the Warsaw Pact would never attack as long as NATO threatened nuclear retaliation.

This calculation was upset by the Soviet deployment of SS-20 missiles from 1977 on to give the Warsaw Pact nuclear as well as conventional superiority within the European theater. This shift in the theater balance followed Soviet attainment of real parity with the United States in strategic nuclear weapons.

These two developments caused Henry Kissinger and some others to doubt the reliability of the American commitment to defend Western Europe with nuclear weapons, since this would make America's own cities more vulnerable.

It was against this background that four former United States officials came up with the sensational proposal last spring that NATO should adopt a policy of no-first-use of nuclear weapons. A Western threat to initiate the use of nuclear arms in response to any conventional attack on Europe was hardly credible, they thought, when the Soviet Union itself possessed nuclear superiority in Europe. And a no-first-use pledge could reassure Western populations that are increasingly worried about nuclear war.

This trial balloon did just the opposite of reassuring the West Germans, however. Officials and academics, conservatives and Social Democrats, all rejected nuclear renunciation and reiterated the need for the threat of NATO nuclear retaliation to provide the greatest deterrent against any conventional attack being made on West Germany.

Instead, they rallied to the far less drastic idea of reducing reliance on nuclear retaliation - or raising the nuclear threshold, as it is commonly called. This is broadly assumed to require better conventional defenses - and it is increasingly assumed to mean phasing out those battlefield nuclear weapons that would only devastate West Germany and, moreover, would require early use before they were overrun in any attack.

These tactical weapons with a range of under 15 miles currently comprise a surprisingly high 60 percent of the some 4,000 US nuclear devices on West German soil. (West Germany has no nuclear weapons of its own and is forbidden by treaty from acquiring them.)

The most coherent proposal in this direction came last summer from Worner himself - then Christian Democratic Union parliamentary party vice-chairman, now defense minister.

Basically, Worner would rely on technology that is just now beginning to come on line to improve West German (and NATO) conventional defenses. He argues that this technology is now shifting to favor the defender rather than the attacker in three areas: serial weapons, precision-guided munitions (PGM), and reconnaissance.

As he explained it in an interview with the Monitor before the change of government, the shift in favor of defense arises because the attacker is the one that has to move. In the new technology the firepower of a dispersed defense dominates the movement of the concentrated attack, rather than vice versa. This should enable NATO to offset the Warsaw Pact superiority of almost 3:1 in tanks and almost 4:1 in artillery in North and Central Europe.

Based on last summer's report by a US-West German study group of military specialists that he commissioned, Worner analyzes the technology this way:

Aerial weapons like the MW-1 make it possible to spread large numbers of small mines or bomblets over wide areas. These can then block a field (and stop a tank offensive) for the several hours it takes until the field has been cleared.

Next, precision-guided munitions will turn the newest generation of antitank weapons into ''fire and forget'' devices. This means that a soldier (or a helicopter), instead of having to remain exposed for the six to 12 seconds it now takes to home in a wire-guided missile on an approaching tank, can emerge from cover for less than a second, fire the missile, and then drop down again.

Moreover, simplified cruise missiles can be sent to attack airfields, bridges , and other behind-the-lines fixed targets that previously would have required too heavy a loss of airplanes to be targeted.

Additionally, new reconnaissance capabilities now in the research and development stage promise to put real-time intelligence from ''deep in the backyard of the enemy'' on the table of the military commander and political decisionmaker. This will be especially important for destroying massed tanks or other second-echelon forces 100 to 150 kilometers behind the front.

And this in turn is especially important in deterring an attack, since Soviet military tactics rely heavily on a three-to-one attack superiority and a fast offensive, in which the second echelon must be ready to replace the decimated first echelon within an hour.

The technology involved here includes drones, missiles with TV screens, and cameras in high flying aircraft that can scan 300 kilometers in any weather.

The main obstacle to boosting NATO's conventional defense has always been the expense, since nuclear weapons are much cheaper than conventional weapons and manpower. Worner has publicly presented a price tag on his recommendations of an additional

billion marks (about $400 million) a year over 10 years. More realistic estimates would perhaps run as much as three times that figure.